If I was to walk by that on the shelf, For sure European in origin, and Mid century in style. The styles for the Edwardian to Art Deco Periods was very different, This is the Mid - Century very popular look for the 40's to 60's. This is also about the time the wash Basin began falling out of favor too, but still made. After the 60's Pretty much the wash basin was gone, and the few made today are more decorative and again usually has the old Victorian to Deco period look, in other words I would say you could rule out Post 60's and style would not match Pre Mid Century. Personally not sure about the horse mark, could just be a flaw on the stoneware or something it was sitting on in the kiln. Something also to note when dating but again is just a rule, early Pottery usually has no glaze on the bottom, Victorian era usually is lacking Glaze on the bottom of the foot only. This is because these pieces was made in a kiln and sat on a rack, more modern industrial ceramic, has the look of such on the bottom.
